MinRead is the minimum slice size passed to a Read call by
Buffer.ReadFrom. As long as the Buffer has at least MinRead bytes beyond
what is required to hold the contents of r, ReadFrom will not grow the
underlying buffer.

Fields interprets s as a sequence of UTF-8-encoded code points.
It splits the slice s around each instance of one or more consecutive white space
characters, as defined by unicode.IsSpace, returning a slice of subslices of s or an
empty slice if s contains only white space.

FieldsFunc interprets s as a sequence of UTF-8-encoded code points.
It splits the slice s at each run of code points c satisfying f(c) and
returns a slice of subslices of s. If all code points in s satisfy f(c), or
len(s) == 0, an empty slice is returned.
FieldsFunc makes no guarantees about the order in which it calls f(c).
If f does not return consistent results for a given c, FieldsFunc may crash.

IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points.
It returns the byte index of the first occurrence in s of any of the Unicode
code points in chars. It returns -1 if chars is empty or if there is no code
point in common.

IndexRune interprets s as a sequence of UTF-8-encoded code points.
It returns the byte index of the first occurrence in s of the given rune.
It returns -1 if rune is not present in s.
If r is utf8.RuneError, it returns the first instance of any
invalid UTF-8 byte sequence.

LastIndexAny interprets s as a sequence of UTF-8-encoded Unicode code
points. It returns the byte index of the last occurrence in s of any of
the Unicode code points in chars. It returns -1 if chars is empty or if
there is no code point in common.

Map returns a copy of the byte slice s with all its characters modified
according to the mapping function. If mapping returns a negative value, the character is
dropped from the byte slice with no replacement. The characters in s and the
output are interpreted as UTF-8-encoded code points.

Replace returns a copy of the slice s with the first n
non-overlapping instances of old replaced by new.
If old is empty, it matches at the beginning of the slice
and after each UTF-8 sequence, yielding up to k+1 replacements
for a k-rune slice.
If n < 0, there is no limit on the number of replacements.

Split slices s into all subslices separated by sep and returns a slice of
the subslices between those separators.
If sep is empty, Split splits after each UTF-8 sequence.
It is equivalent to SplitN with a count of -1.

SplitAfter slices s into all subslices after each instance of sep and
returns a slice of those subslices.
If sep is empty, SplitAfter splits after each UTF-8 sequence.
It is equivalent to SplitAfterN with a count of -1.

SplitAfterN slices s into subslices after each instance of sep and
returns a slice of those subslices.
If sep is empty, SplitAfterN splits after each UTF-8 sequence.
The count determines the number of subslices to return:

n > 0: at most n subslices; the last subslice will be the unsplit remainder.
n == 0: the result is nil (zero subslices)
n < 0: all subslices

SplitN slices s into subslices separated by sep and returns a slice of
the subslices between those separators.
If sep is empty, SplitN splits after each UTF-8 sequence.
The count determines the number of subslices to return:

n > 0: at most n subslices; the last subslice will be the unsplit remainder.
n == 0: the result is nil (zero subslices)
n < 0: all subslices

NewBuffer creates and initializes a new Buffer using buf as its
initial contents. The new Buffer takes ownership of buf, and the
caller should not use buf after this call. NewBuffer is intended to
prepare a Buffer to read existing data. It can also be used to size
the internal buffer for writing. To do that, buf should have the
desired capacity but a length of zero.

In most cases, new(Buffer) (or just declaring a Buffer variable) is
sufficient to initialize a Buffer.

Bytes returns a slice of length b.Len() holding the unread portion of the buffer.
The slice is valid for use only until the next buffer modification (that is,
only until the next call to a method like Read, Write, Reset, or Truncate).
The slice aliases the buffer content at least until the next buffer modification,
so immediate changes to the slice will affect the result of future reads.

Grow grows the buffer's capacity, if necessary, to guarantee space for
another n bytes. After Grow(n), at least n bytes can be written to the
buffer without another allocation.
If n is negative, Grow will panic.
If the buffer can't grow it will panic with ErrTooLarge.

Next returns a slice containing the next n bytes from the buffer,
advancing the buffer as if the bytes had been returned by Read.
If there are fewer than n bytes in the buffer, Next returns the entire buffer.
The slice is only valid until the next call to a read or write method.

Read reads the next len(p) bytes from the buffer or until the buffer
is drained. The return value n is the number of bytes read. If the
buffer has no data to return, err is io.EOF (unless len(p) is zero);
otherwise it is nil.

ReadBytes reads until the first occurrence of delim in the input,
returning a slice containing the data up to and including the delimiter.
If ReadBytes encounters an error before finding a delimiter,
it returns the data read before the error and the error itself (often io.EOF).
ReadBytes returns err != nil if and only if the returned data does not end in
delim.

ReadFrom reads data from r until EOF and appends it to the buffer, growing
the buffer as needed. The return value n is the number of bytes read. Any
error except io.EOF encountered during the read is also returned. If the
buffer becomes too large, ReadFrom will panic with ErrTooLarge.

ReadRune reads and returns the next UTF-8-encoded
Unicode code point from the buffer.
If no bytes are available, the error returned is io.EOF.
If the bytes are an erroneous UTF-8 encoding, it
consumes one byte and returns U+FFFD, 1.

ReadString reads until the first occurrence of delim in the input,
returning a string containing the data up to and including the delimiter.
If ReadString encounters an error before finding a delimiter,
it returns the data read before the error and the error itself (often io.EOF).
ReadString returns err != nil if and only if the returned data does not end
in delim.

UnreadByte unreads the last byte returned by the most recent successful
read operation that read at least one byte. If a write has happened since
the last read, if the last read returned an error, or if the read read zero
bytes, UnreadByte returns an error.

UnreadRune unreads the last rune returned by ReadRune.
If the most recent read or write operation on the buffer was
not a successful ReadRune, UnreadRune returns an error. (In this regard
it is stricter than UnreadByte, which will unread the last byte
from any read operation.)

Write appends the contents of p to the buffer, growing the buffer as
needed. The return value n is the length of p; err is always nil. If the
buffer becomes too large, Write will panic with ErrTooLarge.

WriteByte appends the byte c to the buffer, growing the buffer as needed.
The returned error is always nil, but is included to match bufio.Writer's
WriteByte. If the buffer becomes too large, WriteByte will panic with
ErrTooLarge.

WriteRune appends the UTF-8 encoding of Unicode code point r to the
buffer, returning its length and an error, which is always nil but is
included to match bufio.Writer's WriteRune. The buffer is grown as needed;
if it becomes too large, WriteRune will panic with ErrTooLarge.

WriteString appends the contents of s to the buffer, growing the buffer as
needed. The return value n is the length of s; err is always nil. If the
buffer becomes too large, WriteString will panic with ErrTooLarge.

WriteTo writes data to w until the buffer is drained or an error occurs.
The return value n is the number of bytes written; it always fits into an
int, but it is int64 to match the io.WriterTo interface. Any error
encountered during the write is also returned.

A Reader implements the io.Reader, io.ReaderAt, io.WriterTo, io.Seeker,
io.ByteScanner, and io.RuneScanner interfaces by reading from
a byte slice.
Unlike a Buffer, a Reader is read-only and supports seeking.

Size returns the original length of the underlying byte slice.
Size is the number of bytes available for reading via ReadAt.
The returned value is always the same and is not affected by calls
to any other method.